1. Field of the Invention
The present invention relates to a resonance tone generation apparatus and a resonance tone generation program which are applied to an electronic musical instrument, and retrieve a musical tone signal indicative of a tone of a polyphonic musical instrument from a tone generator of the electronic musical instrument to generate a musical tone signal indicative of a resonance tone which imitates a tone of a vibrating body of the polyphonic musical instrument, the vibrating body being resonated by the musical sound of the polyphonic musical instrument and indicated by the retrieved musical tone signal.
2. Description of the Related Art
Conventionally, there is a known resonance tone generation apparatus such as the one disclosed in Japanese Unexamined Patent Publication No. 63-267999. The resonance tone generation apparatus has twelve resonance tone generation circuits. Each resonance tone generation circuit is assigned one pitch name (pitch class). Each resonance tone generation circuit has a delay circuit for delaying a received musical tone signal for a period of delay time specified for the assigned pitch name, a multiplying circuit for multiplying a predetermined coefficient by the delayed musical tone signal, and an adding circuit for adding the multiplied result to a musical tone signal newly received from a tone generator and inputting the added signal to the delay circuit again. As a result, the resonance tone generation circuit has a plurality of resonance frequencies corresponding to the assigned pitch name. Among frequency components forming the tone indicated by the musical tone signal supplied the resonance tone generation circuit, frequency components different from the resonance frequencies of the resonance tone generation circuit decay immediately, but frequency components which coincide with the resonance frequencies of the resonance tone generation circuit can remain as a resonance tone.